Self and angus g



(No Model.)

H. A. HUNTINGTON. Q-PTOMETEB..

Patented Peb. 12, 1895.v

W/TNESSES.'

THE Nonms PETERS co.. PNeTaLITHo.. wsummnn. n, cA

fto indicate the degree of extension of the` Nrrsn STATES I-IOMER A. HUNTINGTON, OF BOSTON,` MASSACHUSETTS, ASSIGNOR TO HIM- SELF AND ANGUSy G. MCKENZIE, OF SAME PLACE. y

OPTOMETER.

SPECIFICATION forming part of Letters-Patent No. 534,156, dated February 12, 1895. Application tiled December 28,1893. Serial No. 494,929.V (No model.)

To @ZZ whom it may concern:

Beit known that I, HOMER A. HUNTINGTON, of Boston, inA the county of Suffolk and State of Massachusetts, have invented a new and Improved Optometer, of which the following is a specification, reference being had to the annexed drawings, forming a part thereof,in

`which- Figure 1 is a side elevation, partly in section, of my improved optometer. Fig. 2 is a longitudinal section of the lens tube. Fig. 3 is an end elevation of the upper portion of the instrument. Fig. 4 is a plan view of the scale surrounding the vertical axis. Fig. 5 is a plan view ofv anopera glass constructed according to my improvement.

Similar letters of reference indicate corresponding parts in all the views.

The object of myY invention is to construct an optical instrument for quickly and accuratelyvdiagnosing errors of refraction in the human eye. Y i. It is adapted for various optical tests, bu more particularly designed and adapted for determining and correcting astigmatism.

The construction and manner of using the linstrument are as hereinafter described.

` -The main tube A of the optometer carries in its anterior end an achromatic telescope objective B, preferably of short focus, and to the posterior end of said `tube is fitted a draw tube O, provided witha rack a which is operated by a pinion b journaled in the tube A. To the front of the draw tube C is fitted arim D, having an internal groove c which receives the flange d of the eye-piece E, the said ange l being fitted loosely to the' groove in the rim D, so that the eye-piece may be turned on its axis. In the eye-piece E, and preferably a short distance within the posterior end thereof is journaled a lens frame e so that it may be turned on an axis at right angles to the axis of the draw tube O.

The draw tube O is provided with a scale tube. The rim D is furnished with a scale g, and the eye-piece E is provided with an index h which extends over the said scale g, thej -index and scale serving to` show the angular displacement of the eye-piece, and a prolongation t' of the axis of the lens frame ve is furnished with an indexj, which moves in front of a sector-shaped scale k attached to the side of the eye-piece. The extremity of the axis t is provided with a small handle Z.

To the lens frame cv is fitted a negative lens G, of suitable power to act with the objective B as a telescope. The main tubeA is mounted `on a short arm m, connected by a jointogl with a spindle o arranged to turn in astandard H. The joint/rt is provided with a scale p, and the arm m carries an index q, which extends over the scale 1o o'n the joint n. To the top of the standard'H is affixed a scale r, and to the spindle o is secured an index s which moves over the scale r.

The test glasses used in connection with the instrument consist of a +10 and a -IO for correcting high degrees of error. Either of these lenses may be inserted in the lens-holding spring. In Fig. 5, I have shown an opera glass having two .main tubes, two draw tubes, and two sets of lenses arranged in the manner l'already described in connection with Figs. 1 and 2. The axis i of the tilting lens G in this case is provided with a milled head t, by Which'it may be turned, andthe scales are omitted.

I will describe the method of using the instrument for making various tests.

In making a test for hypermetropia,lclose the instrumentshown in Fig. l, so that the scale f indicates zero. I then open it to thev greatest extent which will allow the patient to read the distant types, and put down the amount as manifest hypermetropia.

In the test for simple hypermetropic astigmatism I adjust the instrument as for hypervmetropia, when the hypermetropic meridian Correct this latter dey loo While it is practicable to employ a single telescopic tube for all `proposed tests, I prefer, chieiy for convenience, to employ two, which are similar in their main or most essential features, and arranged parallel. In such case, one such tube, say the one shown in Fig. 2, is particularly adapted for making the test for myopia-that is to say, it is provided with an auxiliary minus lens, or one which is much stronger than the corresponding lens in the other parallel tube.

In Fig. 2, the draw-tube, O, is provided with a scale f', to indicate the adjustment of the draw-tube, or, in other words, to indicate the distance between the obj ect-glass, B, and lens, G; but it will be observed the said scale reads from rightto left, or opposite to the scale,f, in Fig. l.

In making the test for myopia, the instrument (Fig. 2) is first opened to its fullest extent, `or until the scale, f', indicates zero, and then closed as far as permitted by the normal vision of the patient.

For simple myopie astigmatism; with the scale f on the draw tube C indicatingzero, and the axis of the eye piece at right angles to the astigmatie meridian, tilt the lens G until the patients vision is` normal.

For compound myopie astigmatism; correct the meridian of least astigmatism, and then, by tilting the lens, G, correct the me ridian at right angles to that of the meridian of least astigmatism.

For mixed astigmatism; correct by the rules for simple hypermetropic astigmatism, first making one meridian emmetropic, thus converting the case into one of simple myopie astigmatism.

In carrying out myinvention, I intend applying it not only for the purposes above indicated, but also in other practical and strictly commercial ways, for example, in an opera glass, as shown in Fig. 5.

By the mere addition of the scales, p and r, (Fig. 1,) tothe standard of the instrument, it is adapted for testing dis-equilibrium of the ocular muscles, and thus dispenses with the necessity of using prisms for that purpose. In this test, one eye of the patient is directed through the instrument at the object, e. g., a circle, and sees it magnified, while with his other uncovered eye he sees the same object of its natural size, equilibrium of his ocular muscles beingdemonstrated when the smaller circle seen with his natural eye seems to him to lie centrally Within the larger circie seen through the instrument, scales 19 and r both standing at zero.

It the circles are not so seen, the movements ot' the telescope in its horizontal and vertical planes necessary to make the circles so appear, are seen at scales p and r Where 'their prismatic value is read.

My optometer obviates the necessity of using a multiplicity of lenses, and enables the optieian to make all necessary tests with a single, simple instrument, which is perfectly accurate and comparatively inexpensive.

Having thusdescribed my invention, I claim as new and desire to secure by Letters Patentl. An optometer, comprising a suitable lens support, and a lens which is pivoted therein on a diametric axis, e., on an axis at right angles to its principal optical axis, whereby it is adapted to betilted and placed at different inclinations, or angles, to the line of vision, corresponding to the existing abnormal refraction, and means for indicating the lenticular, astigmatic corrections required, as specilied.

2. In an instrument for correcting astigmatism, the combination with a suitable lens support, of a lens which is rotatable about. its priucipalaxis, and also pivoted on a diametric axis, or axis at right angles to said priucipaloptical axis, substantially as shown and described.

3. In an improved optometer, a suitable leus support, a lens arranged to turn on an axis co-incident with its principal optical axis, and rotatable on a diametric axis, or

one which is at right angles to such principal optical axis, and two scales arranged as shown, one for indicating the angle formed by the plane of the lens with the line of vision, the other scale being for indicating the angular displacement of the lens in a vertical plane, as and for the purposes specified.

4t. The improved optometer, comprising a two-part telescopic tube, an object glass, and a lens, which is rotatable on an axis coincident with its principal optical axis, and also rotatable on a diametric axis, i. c., an axis which is at right angles to such principal optical axis, substantially as shown and described.

I-IOMER A. HUNTINGTON. I'Vitnesses:

FREDERICK A. DAVIS, WILEY P. SWIFT.

IOO 

